BBC
BBC's Olympic commentators hold lip microphones during the curling event
If you are watching the BBC's coverage of the Sochi Olympics you may have noticed some funny-looking microphones being used by some of the commentators, such as those at the curling venue above.
Those are called "lip mics" or "commentator's lip microphones." These mics are much more common in Europe and were designed by the BBC in the 1930s to block out the noise generated by the crowd at sporting events such as cricket.
Specifically, sound that is generated directly in front of the microphone is picked up while noise that comes from the sides is cancelled out. The cover on the mics make sure the speaker's mouth is the correct distance from the microphone and may also serve to block sound generated by nasal air.
However, it is easy to imagine why most commentators prefer more modern headsets.